JP7528262B2 - Batteries and electronic devices - Google Patents

Description

This application relates to the field of battery technology, and in particular to batteries and electronic devices.

A battery plate includes a current collector, an active material layer, and a tab, where the active material layer covers the surface of the current collector and the tab is welded to the current collector. To facilitate welding of the tab, it is necessary to remove a portion of the active material layer on the front and back surfaces of the battery plate to form a groove, expose the current collector in the groove, and weld the tab to the current collector in the groove.

However, the groove areas on the battery plates are prone to short circuits and lithium deposition problems, which affect the safety performance of the battery.

To solve the above technical problems, the present application provides a battery and electronic device that is advantageous in improving the safety performance of the battery by avoiding the occurrence of short circuits and lithium precipitation problems in the groove areas of the battery plates.

To achieve the above objective, the embodiments of the present application provide the following technical means:

In a first aspect, an embodiment of the present application provides a battery, the battery including a first plate, a second plate, and a separator, the first plate, the separator, and the second plate being sequentially stacked and wound and installed, the first plate including a first current collector and a first tab, the first current collector including a first surface and a second surface, the first surface and the second surface both being provided with a first active material layer, the first active material layer being provided with a first groove and a second groove, the first groove and the second groove being located on the first surface and the second surface, respectively, and being positioned opposite each other, the first tab being welded into the first groove, the first groove being covered with at least one insulating layer, and the second groove being covered with at least one insulating layer.

The battery provided by the embodiment of the present application covers the first groove with at least one insulating layer and the second groove with at least one insulating layer, which not only prevents short circuit problems from occurring in the first and second groove regions, but also prevents lithium precipitation problems from occurring in the first and second grooves, and further helps improve the safety performance of the battery.

Optionally, the first groove is covered with at least two insulating layers.

Optionally, the second groove is covered with an insulating layer, and at least one insulating layer is provided in the area of the second plate facing the second groove.

Optionally, in the second plate, the length and/or width of the insulating layer in the area facing the second groove is not greater than the corresponding length and/or width of the insulating layer in the second groove.

Optionally, the second groove is covered with at least two insulating layers.

Optionally, of the at least two insulating layers in the first groove, some or all of the insulating layers cover the first groove.

Optionally, the second plate includes a second current collector and a second tab, both opposing sides of the second current collector are provided with a second active material layer, the second active material layer is provided with a third groove and a fourth groove, the third groove and the fourth groove are located on both opposing sides of the second current collector and are positioned opposite each other, the second tab is welded into the third groove, both the third groove and the fourth groove are covered with one insulating layer, the first plate is provided with one insulating layer in a region facing the third groove, and the first plate is provided with one insulating layer in a region facing the fourth groove.

Optionally, the first groove, the second groove, the third groove, the fourth groove and the insulating layer are all rectangular, and the insulating layer is adhesive paper.

Optionally, in the first plate, the length and/or width of the insulating layer in the area facing the third groove is not greater than the corresponding length and/or width of the insulating layer in the third groove, and in the first plate, the length and/or width of the insulating layer in the area facing the fourth groove is not greater than the corresponding length and/or width of the insulating layer in the fourth groove.

Optionally, the first electrode plate is a negative electrode plate, the second electrode plate is a positive electrode plate, the insulating layer covering the first groove is provided on a separator between the first groove and the second electrode plate, and the insulating layer is used to prevent the passage of lithium ions.

Optionally, the insulating layer is located on the side of the separator facing the first plate, and/or the insulating layer is located on the side of the separator facing the second plate.

Optionally, the insulating layer is adhered to the separator via a first adhesive layer, the first adhesive layer being a hot melt adhesive layer that is non-tacky at room temperature.

Optionally, a second adhesive layer is provided on the surface of the insulating layer opposite the separator, and the second adhesive layer is a pressure-sensitive adhesive layer that can be swelled by the electrolyte.

Optionally, the insulating layer is applied to the surface of the separator by spray coating.

Optionally, the insulating layer contains polyester resin and/or the thickness of the insulating layer is 10 μm to 20 μm.

Optionally, the separator is selected from polyethylenes or polypropylenes, and the insulating layer is formed after the portion of the separator covering the first groove is heat-treated, and/or the second electrode plate includes a second current collector and a second active material layer, the second active material layer covers the surface of the second current collector, and the second current collector is provided with a non-active material layer region, and the non-active material layer region faces the first groove.

Optionally, the area of the first groove is greater than the area of the second groove.

Optionally, in the direction of the connecting line between the first surface and the second surface, the projection of the first groove completely covers the projection of the second groove.

Optionally, the cross sections of the first groove and the second groove are both rectangular or circular, and the cross sections are planes perpendicular to the connection line between the first surface and the second surface.

Optionally, when the cross sections of the first groove and the second groove are rectangular, the length of the side of the first groove is greater than the length of the side of the second groove, and the width of the side of the first groove is greater than the width of the side of the second groove.

Optionally, the area of the second groove is 60-90% of the area of the first groove.

Optionally, the plane formed by the central axis of the first groove and the central axis of the second groove overlaps or is parallel to the connection line between the first surface and the second surface.

Optionally, the minimum distance between adjacent sides of the first groove and the second groove is n, where 0.5 mm≦n≦3.5 mm.

Optionally, the maximum distance between adjacent sides of the first groove and the second groove is x, where 0.5 mm≦x≦3.5 mm.

Optionally, the second plate includes a second current collector and a second tab, both opposing surfaces of the second current collector are provided with a second active material layer, the second active material layer is provided with a third groove and a fourth groove, the third groove and the fourth groove are located on both opposing surfaces of the second current collector, and are positioned opposite each other, the second tab is welded into the third groove, and the area of the third groove is larger than the area of the fourth groove.

In a second aspect, an embodiment of the present application provides an electronic device, the electronic device including a battery as described in any one of the above.

The electronic device provided by the embodiment of the present application includes a battery, and when the safety performance of the battery is improved, the safety performance of the electronic device including the battery is also improved.

In a third aspect, an embodiment of the present application provides a method for manufacturing a winding core for a battery, the method comprising: providing a positive electrode plate, an insulating layer, a negative electrode plate, and a separator, the negative electrode plate including a first current collector and a first tab, a first active material layer being provided on both opposing sides of the first current collector, a first groove being provided in the first active material layer, and the first tab being welded into the first groove; providing a first adhesive layer on one side of the insulating layer, and providing a second adhesive layer on the other side of the insulating layer, the first adhesive layer being adhesive at room temperature. the hot melt adhesive layer is not a layer on the surface of the insulating layer on which the second adhesive layer is provided, adhering the surface of the insulating layer on which the second adhesive layer is provided to a predetermined position of the positive electrode plate, stacking the separator and the negative electrode plate in sequence on the surface of the positive electrode plate on which the insulating layer is attached so that the first groove faces the separator, winding the stacked structure so that the insulating layer for preventing the passage of lithium ions covers the first groove to form a winding core, and subjecting the winding core to a thermocompression treatment so that the surface of the insulating layer on which the first adhesive layer is provided is adhered to the separator.

The manufacturing method of the battery winding core provided by the embodiment of the present application is advantageous in that the insulating layer better covers the first groove, thereby preventing short circuits and lithium precipitation problems from occurring in the first groove area, and further advantageous in improving the safety performance of the battery.

Hereinafter, in order to more clearly explain the technical solutions of the embodiments of the present application, the drawings necessary for the embodiments will be briefly described. It should be understood that the following drawings only show specific embodiments of the present application, and should not be considered as limiting the scope. Those skilled in the art can also obtain other related drawings based on these drawings without any creative work.
FIG. 2 is a schematic diagram of the top surface of a first plate provided by an embodiment of the present application. FIG. 2 is a schematic cross-sectional view of a first electrode plate provided by an embodiment of the present application. FIG. 2 is a schematic diagram of a winding core provided by an embodiment of the present application. FIG. 2 is a schematic diagram of the top surface of a second electrode plate provided by an embodiment of the present application. FIG. 2 is a schematic diagram of another first plate provided by an embodiment of the present application. 1 is a schematic diagram of a partial structure of a battery provided by an embodiment of the present application. FIG. 2 is a schematic diagram 2 of a partial structure of a battery provided by an embodiment of the present application. FIG. 3 is a schematic diagram of a partial structure of a battery provided by an embodiment of the present application. 4 is a schematic diagram of a partial structure of a battery provided by an embodiment of the present application. FIG. 2 is a schematic structural diagram of a battery plate provided by an embodiment of the present application. FIG. 2 is a side view of a battery plate provided by an embodiment of the present application. FIG. 2 is a schematic structural diagram of a first side of a battery plate provided by an embodiment of the present application. FIG. 2 is a schematic structural diagram of a second side of a battery plate provided by an embodiment of the present application.

In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application are described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Generally, the components of the embodiments of the present application as generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application as claimed, but rather represents only certain embodiments of the present application. All other embodiments that a person skilled in the art would obtain without creative labor based on the embodiments of the present application are all within the scope of the claims of the present application.

Figure 1 is a schematic diagram of the top surface of a first electrode plate provided by an embodiment of the present application, Figure 2 is a schematic cross-sectional view of the first electrode plate provided by an embodiment of the present application, Figure 3 is a schematic diagram of a winding core provided by an embodiment of the present application, Figure 4 is a schematic diagram of the top surface of a second electrode plate provided by an embodiment of the present application, and Figure 5 is a schematic diagram of another first electrode plate provided by an embodiment of the present application.

Refer to Figures 1 to 5. This embodiment provides a battery, which includes a first plate 11, a second plate 12, a first tab 111, and a separator, and the first plate 11, the separator, and the second plate 12 are sequentially stacked and wound and installed. The first plate 11 includes a first current collector, and a first active material layer is provided on both the upper and lower surfaces of the first current collector, and the first active material layer is provided with a first groove 112 and a second groove, which are opposite to each other and located on the upper and lower surfaces of the first current collector, respectively. The first tab 111 is welded to the first groove 112, and the first groove 112 is covered with at least two layers of insulating layers, and the second groove to which the tab is not welded is covered with at least one layer of insulating layer.

In this embodiment, the first groove 112 is located on the upper surface of the first current collector, the area of the first groove is removed, and the bottom of the first groove is the first current collector. The second groove is located on the lower surface of the first current collector, the area of the second groove is removed, and the bottom of the second groove is the first current collector. The first groove 112 faces the second electrode plate 12, and the second groove faces the second electrode plate 12. The first electrode plate 11 usually refers to the positive electrode plate in a battery structure, and the second electrode plate 12 usually refers to the negative electrode plate in a battery structure.

The first groove 112 is covered with at least two insulating layers, which are used for process error proofing. If one of the insulating layers is not applied according to a preset standard, the insulating layer application device can detect the application of the first insulating layer that does not meet the standard when applying the second insulating layer, and correct it immediately. If one of the insulating layers is not applied or peeled off, the first groove 112 is further covered with at least one other insulating layer. This improves the safety performance and reliability of the battery structure, and the first groove 112 is covered more firmly. The insulating layer application device is simpler, and the device is easier to repair.

Taking the example of the first groove 112 being covered with two insulating layers, the two insulating layers are a first insulating sublayer and a second insulating sublayer, and the size of the first insulating sublayer may be larger or smaller than the size of the second insulating sublayer, and the size of the first insulating sublayer may be equal to the size of the second insulating sublayer, but this embodiment is not limited thereto, and the first insulating sublayer or the second insulating sublayer may completely cover the first groove 112. In this way, the settings for size and positional relationship between the insulating layers are relatively loose, and the cumulative error due to the relatively strict alignment and size relationship is avoided, the risk of internal short circuit in the battery is reduced, the safety of the battery structure is relatively high, the integrity and stability of the core are relatively high, the size of the insulating layer can be set smaller, and the energy density of the core is improved.

In one alternative embodiment, the second groove is covered with an insulating layer, and the area of the second plate 12 facing the second groove is provided with at least one insulating layer.

The second groove faces the second electrode plate 12, one insulating layer covering the second groove is located on the first electrode plate 11, and the other insulating layer covering the second groove is located on the second electrode plate 12.

As an optional embodiment, the length and/or width of the insulating layer in the area of the second plate 12 facing the second groove is not greater than the corresponding length and/or width of the insulating layer in the second groove. This embodiment reduces the possibility of lithium deposition occurring in the battery and improves the safety of the battery structure.

In one optional embodiment, the second groove is covered with at least two insulating layers.

In this embodiment, the first groove 112 is covered with at least two insulating layers, and the second groove to which the tab is not welded is covered with at least two insulating layers, and the insulating layers covering the first groove 112 and the second groove are shown in FIG. 3 as 113, both located on the first plate 11. Similarly, the size and positional relationship between the insulating layers in the second groove is loosely set, which avoids the cumulative error due to tighter alignment and size relationship, reduces the risk of internal short circuit in the battery, and provides high core integrity. This embodiment reduces the risk of the tab breaking through the insulating layer and causing an internal short circuit in the battery.

As an optional embodiment, part or all of the at least two insulating layers in the first groove 112 cover the first groove 112.

In this embodiment, a portion of the at least two insulating layers in the first groove 112 covers the first groove 112, and the energy density of the battery structure is high. Alternatively, the entire at least two insulating layers in the first groove 112 covers the first groove 112, and the first groove 112 is more firmly covered.

As an alternative embodiment, the second electrode plate 12 includes a second current collector, and a second active material layer is provided on both the upper and lower surfaces of the second current collector, and the second active material layer is provided with a third groove 121 and a fourth groove, which are arranged opposite each other and located on the upper and lower surfaces of the second current collector, respectively, a second tab 122 is welded to the third groove 121, and both the third groove 121 and the fourth groove are covered with one layer of insulating layer, and a layer of insulating layer is provided in the area facing the third groove 121 in the first electrode plate 11, and a layer of insulating layer is provided in the area facing the fourth groove in the first electrode plate 11.

The first current collector and the second current collector may have the same constituents, and the first active material layer and the second active material layer may have the same constituents. The third groove 121 is located on the upper surface of the second current collector, the area of the third groove 121 is removed from the active material, and the bottom of the third groove 121 is the second current collector. The fourth groove is located on the lower surface of the second current collector, the area of the fourth groove is removed from the active material, and the bottom of the fourth groove is the second current collector. The third groove 121 faces the first electrode plate 11, and the fourth groove faces the first electrode plate 11.

The third groove 121 and the fourth groove are both covered with an insulating layer, as shown by reference numeral 123 in FIG. 3. An insulating layer is provided in the area of the first electrode plate 11 facing the third groove 121, and an insulating layer is provided in the area of the first electrode plate 11 facing the fourth groove, as shown by reference numeral 114 in FIG. 3. One insulating layer covering the third groove 121 is located on the second electrode plate 12, and the other insulating layer covering the third groove 121 is located on the first electrode plate 11. One insulating layer covering the fourth groove is located on the second electrode plate 12, and the other insulating layer covering the fourth groove is located on the first electrode plate 11.

As an optional embodiment, the first groove 112, the second groove, the third groove 121, the fourth groove and the insulating layer are all rectangular, and the insulating layer is adhesive paper.

In this embodiment, the first groove 112, the second groove, the third groove 121, the fourth groove and the insulating layer are all rectangular, which makes it easier to cover the grooves, reduces the difficulty of applying the adhesive paper, improves the accuracy of covering the grooves, and improves the safety performance of the battery.

As an alternative embodiment, the length and/or width of the insulating layer in the region facing the third groove 121 on the first electrode plate 11 is not greater than the corresponding length and/or width of the insulating layer in the third groove 121, and the length and/or width of the insulating layer in the region facing the fourth groove on the first electrode plate 11 is not greater than the corresponding length and/or width of the insulating layer in the fourth groove.

This embodiment reduces the possibility of lithium deposition occurring in the battery and improves the safety performance of the battery structure. When the insulating layers in the grooves are all located on their own plates, the size and positional relationship between the insulating layers is loosely set. When the insulating layers in the grooves are each located on a different plate, the size and positional relationship between the insulating layers is tightly set.

Reference numeral 115 in FIG. 1, reference numeral 116 in FIG. 2, reference numerals 113, 114 and 123 in FIG. 3, reference numeral 124 in FIG. 4, and reference numeral 116 in FIG. 5 are all insulating layers.

In this embodiment, the battery includes a first electrode plate 11, a second electrode plate 12, a first tab 111, and a separator, and the first electrode plate 11, the separator, and the second electrode plate 12 are sequentially stacked and wound and installed. The first electrode plate 11 includes a first current collector, and a first active material layer is provided on both the upper and lower surfaces of the first current collector. The first active material layer is provided with a first groove 112 and a second groove, and the first groove 112 and the second groove are provided opposite each other and are located on the upper and lower surfaces of the first current collector, respectively. The first tab 111 is welded to the first groove 112, and the first groove 112 is covered with at least two insulating layers. The second groove to which the tab is not welded is covered with at least one insulating layer. This improves the safety performance of the battery structure compared to the conventional technology in which a third insulating layer and a fourth insulating layer are provided on the second plate to cover the first weld seam, and cumulative errors due to the size and position of the insulating layers can easily lead to a risk of internal short circuit in the battery.

In batteries with a winding core, the tab attachment technique is usually adopted, that is, the active material layer in a part of the plate surface is removed in a specific process, and a tab is welded on the exposed current collector after removing the active material layer of the plate. However, the exposed current collector is not completely covered after the tab is welded to the current collector of the plate, that is, there is still exposed current collector around the tab. Lithium ion batteries have a lithium deposition phenomenon during charging. If there is an active material layer on the positive plate opposite the exposed current collector on the negative plate, lithium ions from the active material layer will pass through the separator between the positive and negative plates and deposit metallic lithium on the exposed current collector surface of the negative plate, which may cause thermal runaway or safety accidents of the lithium ion battery.

Figure 6 is a schematic diagram 1 of a partial structure of a battery provided by an embodiment of the present application, Figure 7 is a schematic diagram 2 of a partial structure of a battery provided by an embodiment of the present application, Figure 8 is a schematic diagram 3 of a partial structure of a battery provided by an embodiment of the present application, and Figure 9 is a schematic diagram 4 of a partial structure of a battery provided by an embodiment of the present application.

Refer to Figures 6 to 9. In order to solve the above technical problems, this embodiment provides a battery including a positive electrode plate 10, a negative electrode plate 20, and a separator 30 located between the positive electrode plate 10 and the negative electrode plate 20, where the separator 30 can insulate the positive electrode plate 10 and the negative electrode plate 20 of the winding core from each other, and the separator 30 has pores through which lithium ions can pass, ensuring that the lithium ion battery with the winding core operates normally.

Specifically, when a lithium-ion battery is charged, lithium ions are released from the crystal lattice of the positive electrode material, pass through the separator together with the electrolyte, and then insert into the crystal lattice of the negative electrode material, making the negative electrode lithium-rich and the positive electrode lithium-poor. When a lithium-ion battery is discharged, lithium ions are released from the crystal lattice of the negative electrode material, pass through the separator together with the electrolyte, and then insert into the crystal lattice of the positive electrode material, making the positive electrode lithium-rich and the negative electrode lithium-poor.

The negative electrode plate 20 of this embodiment includes a negative electrode collector 21, a negative electrode active material layer 22, and a negative tab 23 arranged on the surface of the negative electrode collector 21. The negative tab 23 may be arranged on the surface of the negative electrode collector 21 in the form of welding, or in other forms. Specifically, the negative electrode active material layer 22 covers the surface of the negative electrode collector 21, and the negative electrode active material layer 22 has a first groove 24 that avoids the negative tab 23, that is, the surface of the negative electrode collector 21 located in the first groove 24 does not cover the negative electrode active material layer 22, and the negative tab 23 is located in the first groove 24.

Typically, to facilitate placement of the negative tab 23 in the first groove 24 on the surface of the negative electrode current collector, the area of the first groove 24 is set to be larger than the area of the negative tab 23 located in the first groove 24, i.e., the negative tab 23 placed in the first groove 24 does not completely cover the negative electrode current collector 21 exposed in the first groove 24, so that there is exposed negative electrode current collector 21 around the negative tab 23. During cycling of the lithium-ion battery, especially during charging of the lithium-ion battery, lithium ions in the electrolyte may precipitate metallic lithium on the surface of the exposed negative electrode current collector 21 around the negative tab 23, which may cause the lithium-ion battery to thermally run away and cause a safety accident.

In this embodiment, the separator between the first groove 24 and the positive electrode plate 10 is provided with an insulating layer 31 that covers the first groove 24. This insulating layer 31 can prevent lithium ions on the positive electrode plate 10 located on the opposite side of the first groove 24 from entering the first groove 24 through the insulating layer 31. This can prevent lithium ions from depositing metallic lithium in the first groove 24 and adhering to the exposed surface of the negative electrode current collector 21 around the negative tab 23, and further contributes to preventing safety accidents due to thermal runaway of the lithium ion battery.

It should be understood that providing an insulating layer 31 to cover the first groove 24 requires that the size of the insulating layer 31 be larger than the size of the first groove 24, so that the insulating layer 31 can completely cover the first groove 24 after winding of the core is complete, preventing lithium ions from entering the first groove 24.

In a specific embodiment, the winding core of the lithium ion battery is configured to include a positive electrode plate 10, a negative electrode plate 20, and a separator 30 located between the positive electrode plate 10 and the negative electrode plate 20, the negative electrode plate 20 includes a negative electrode collector 21 and a negative electrode active material layer 22 covering the surface of the negative electrode collector, the surface of the negative electrode collector 21 has a first groove 24 that is not covered by the negative electrode active material layer 22, and a negative tab 23 is provided on the surface of the negative electrode collector 21 in the first groove 24, thereby ensuring that the winding core functions normally in the lithium ion battery. During charging of the lithium-ion battery, in order to prevent lithium ions released from the positive electrode plate 10 located on the opposite side of the first groove 24 from entering the first groove 24 and depositing metallic lithium on the surface of the negative electrode collector 21, an insulating layer 31 covering the first groove 24 is provided on the separator located between the first groove 24 and the positive electrode plate 10. The insulating layer 31 prevents lithium ions released from the positive electrode plate 10 from entering the first groove 24, and can prevent lithium ions from depositing metallic lithium on the surface of the negative electrode collector 21 in the first groove 24. This is advantageous for preventing safety accidents due to thermal runaway of the lithium-ion battery, and is also advantageous for reducing safety risks due to the deposition of metallic lithium during rapid charging of the lithium-ion battery.

The winding core of this embodiment includes a positive electrode plate 10, a negative electrode plate 20, and a separator 30 located between the positive electrode plate 10 and the negative electrode plate 20. The separator 30 is used to ensure insulation between the positive electrode plate 10 and the negative electrode plate 20. The negative electrode plate 20 includes a negative electrode collector 21, a negative electrode active material layer 22, and a negative tab 23 provided on the surface of the negative electrode collector 21. The negative electrode active material layer 22 covers the surface of the negative electrode collector 21, and the negative electrode active material layer 22 has a first groove 24 that avoids the tab 23. The negative tab 23 provided on the surface of the negative electrode collector 21 is located in the first groove 24. An insulating layer 31 that prevents the passage of lithium ions is provided on the separator 30 between the first groove 24 and the positive electrode plate 10, and the insulating layer 31 covers the first groove 24. That is, by making the size of the insulating layer 31 larger than the size of the first groove 24, the first groove 24 can be completely covered, so that the lithium ions of the positive electrode plate 10 can be prevented from passing through the insulating layer 31 and entering the first groove 24, and the lithium ions can be prevented from depositing metallic lithium in the first groove 24 and attaching to the negative electrode current collector 21. This is advantageous for preventing safety accidents due to thermal runaway of the lithium ion battery, and is also advantageous for reducing safety risks due to the deposition of metallic lithium during rapid charging of the lithium ion battery.

Embodiments in which an insulating layer 31 is provided between the first groove 24 and the positive electrode plate 10 to cover the first groove 24 include, but are not limited to, the following three possible embodiments.

In a first feasible embodiment, as shown in FIG. 6, an insulating layer 31 is provided on the surface of the separator 30 facing the positive electrode plate 10. When this is specifically realized, the lithium ions released from the positive electrode plate 10 are blocked by the insulating layer 31 before passing through the separator 30, so that the lithium ions cannot pass through the insulating layer 31 and enter the first groove 24. Furthermore, the lithium ions precipitate metallic lithium on the surface of the negative electrode current collector 21 in the first groove 24, thereby avoiding a safety accident caused by thermal runaway of the lithium ion battery.

In a second feasible embodiment, as shown in FIG. 7, an insulating layer 31 is provided on the surface of the separator 30 facing the negative electrode plate 20. When this is specifically realized, lithium ions released from the positive electrode plate 10 pass through the separator 30 and are blocked by the insulating layer 31. This prevents the lithium ions from passing through the insulating layer 31 and entering the first groove 24. Furthermore, the lithium ions precipitate metallic lithium on the surface of the negative electrode current collector 21 in the first groove 24, thereby avoiding a safety accident caused by thermal runaway of the lithium ion battery.

In a third feasible embodiment, as shown in FIG. 8, the surface of the separator 30 facing the positive electrode plate 10 and the surface of the separator 30 facing the negative electrode plate 20 are both provided with an insulating layer 31. In a specific implementation, the lithium ions released from the positive electrode plate 10 are blocked by the insulating layer 31 before passing through the separator 30, so that the lithium ions cannot pass through the insulating layer 31 and enter the first groove 24. The insulating layer 31 is provided between the positive electrode plate 10 and the separator 30 and between the negative electrode plate 20 and the separator 30, so that the lithium ions can be better prevented from entering the first groove 24. This allows the lithium ions to precipitate metallic lithium on the surface of the negative electrode current collector 21 in the first groove 24, thereby avoiding safety accidents caused by thermal runaway of the lithium ion battery.

Specifically, the embodiment of providing the insulating layer 31 on the separator 30 between the first groove 24 and the positive electrode plate 10 includes, but is not limited to, the following three possible implementations.
In the first embodiment, the insulating layer 31 is adhered to the surface of the separator 30, and for example, a first adhesive layer is provided on the surface of the insulating layer 31 facing the separator 30, so that the insulating layer 31 can be adhered to the separator 30 via the first adhesive layer. The insulating layer 31 may be adhered to the surface of the separator 30 facing the positive electrode plate 10, or to the surface of the separator 30 facing the negative electrode plate 20, or to both sides of the separator 30. The first adhesive layer may be a hot melt adhesive layer that is not adhesive at room temperature, where room temperature means room temperature in a normal environment, that is, the hot melt adhesive layer does not have adhesiveness in a room temperature environment, and the first adhesive layer may be another adhesive layer that can adhere the insulating layer 31 to the separator 30, and the description thereof will be omitted here.

In a specific case, during the process of winding the core, the insulating layer 31 is adhered to a position corresponding to the first groove 24 of the separator 30. Whether it is adhered to the surface of the separator 30 facing the positive electrode plate 10, or to the surface of the separator 30 facing the negative electrode plate 20, or the insulating layer 31 is adhered to both sides of the separator 30, the insulating layer 31 only needs to cover the first groove 24 after winding of the winding core is completed, thereby preventing lithium ions from passing through the insulating layer 31 and entering the first groove 24. Furthermore, the lithium ions precipitate metallic lithium on the surface of the negative electrode current collector 21 in the first groove 24, thereby avoiding safety accidents due to thermal runaway of the lithium ion battery.

Furthermore, a second adhesive layer may be provided on the surface of the insulating layer 31 opposite the separator 30, and the second adhesive layer may be provided as a pressure-sensitive adhesive layer that can swell with an electrolyte solution. The pressure-sensitive adhesive layer that can swell with an electrolyte solution swells when it encounters the electrolyte solution and detaches from the adhesive. Here, the pressure-sensitive adhesive layer that can swell with an electrolyte solution uses epoxies, polyurethanes, acrylics, or rubbers as the adhesive, so that after the pressure-sensitive adhesive layer that can swell with an electrolyte solution is immersed in the electrolyte solution, the adhesive strength can be reduced to within 5% of the initial state, that is, the initial adhesive strength is 0.1 to 0.3 N/mm, and the adhesive strength after immersion in the electrolyte solution is less than 0.015 N/mm, preferably 0.010 N/mm or less.

In a specific example, when the insulating layer 31 is located between the positive electrode plate 10 and the separator 30, in the process of winding the core, the surface of the insulating layer 31 on which the second adhesive layer, which is a pressure-sensitive adhesive layer that can swell with an electrolyte, is attached to a predetermined position on the positive electrode plate 10 and wound up, where the predetermined position is a position that is aligned with the first groove 24 in the positive electrode plate 10 after the core winding is completed, that is, the insulating layer 31 attached to the predetermined position covers the first groove 24 after the core winding is completed, and the surface of the insulating layer 31 on which the first adhesive layer, which is a hot melt adhesive layer that is not sticky at room temperature, is provided. is in contact with the separator 30, and after winding is completed, the core on which winding has been completed is subjected to a heat press, the heat press temperature may be 30°C to 90°C, and the heat press increases the adhesion of the first adhesive layer in contact with the separator 30, i.e., the hot melt adhesive layer which is not sticky at room temperature, thereby bonding it to the separator 30, the winding core is enclosed in a shell and an electrolyte is injected, and then the electrolyte causes the second adhesive layer, which is a pressure-sensitive adhesive layer that can be swelled by the electrolyte, to swell and detach from the positive electrode plate 10, and finally the insulating layer 31 is bonded to the separator 30, without impairing the performance of the positive electrode plate 10. Here, by adhering the insulating layer 31 to the positive electrode plate 10, the insulating layer 31 can be positioned better, ensuring that the insulating layer 31 covers the first groove 24 relatively accurately after winding is completed. By making the first adhesive layer a hot melt adhesive layer that is not sticky at room temperature, the insulating layer 31 is adhered to the conveying roller of the device during the winding process, preventing the adhesive layer from falling off or the electrode plate from tearing. It can also be prevented that too much dust is adsorbed on the surface of the insulating layer 31, which would adversely affect the safety performance of the battery.

In a second embodiment, the insulating layer 31 may be attached to the surface of the separator 30 in the form of a spray coating. Specifically, the insulating layer 31 may be attached to the surface of the separator 30 facing the positive electrode plate 10, or may be attached to the surface of the separator 30 facing the negative electrode plate 20, or both sides of the separator 30 may be spray-coated with the insulating layer 31. The insulating layer formed in the form of a spray coating may be a polypropylene layer, a polyethylene layer, or other polymer layer, or may be a metal layer, other inorganic layer, etc.

The insulating layer 31 may be provided on the surface of the separator 30 in other forms. Alternatively, the insulating layer 31 may be provided between the separator 30 and the positive electrode plate 10, or between the separator 30 and the negative electrode plate 20, depending on actual needs.

Optionally, the material used to process and form the insulating layer 31 may contain polyester resin, or may contain other materials that can meet the requirements for the insulating layer 31 of this embodiment, so we will not explain them here.

The thickness of the insulating layer 31 in this embodiment can be set to 10 μm to 20 μm to ensure that the thickness of the insulating layer 31 does not adversely affect the performance of the winding core.

In a third embodiment, the portion of the separator 30 covering the first groove 24 can be heat-treated to form an insulating layer 31. Here, the separator 30 is selected from polyethylenes or polypropylenes, and the polyethylene or polypropylene separator 30 can close the pores in the separator 30 through which lithium ions pass after heat treatment, thereby forming an insulating layer 31 that can prevent the passage of lithium ions.

Here, the form of heat treatment of the portion covering the first groove 24 of the separator 30 may be contact heating, for example, by directly contacting and heating the portion covering the first groove 24 of the separator 30 with a heating plate to close the hole in the portion covering the first groove 24 of the separator 30, or non-contact heating, for example, by irradiating the portion covering the first groove 24 of the separator 30 with an infrared lamp to heat the portion covering the first groove 24 of the separator 30 to close the hole, and the temperature for heat treatment of the portion covering the first groove 24 of the separator 30 may be 120°C to 250°C, and the heat treatment time may be 1 s to 5 s.

Furthermore, the positive electrode plate 10 includes a positive electrode collector 110 and a positive electrode active material layer 120, and the positive electrode active material layer 120 covers the surface of the positive electrode collector 110. The positive electrode collector 110 is provided with a non-active material layer region 13. The non-active material layer region 13 faces the first groove 24, so that the positive electrode plate 10 facing the first groove 24 does not have active material that generates lithium ions. This prevents lithium ions released from the positive electrode plate 10 facing the first groove 24 from entering the first groove 24 and depositing metallic lithium on the surface of the negative electrode collector 21 in the first groove 24. This is advantageous in preventing safety accidents due to thermal runaway of the lithium ion battery, and at the same time, is advantageous in reducing safety risks due to the deposition of metallic lithium during rapid charging of the lithium ion battery.

The present embodiment further provides a method for manufacturing a battery winding core, the method including the following steps:

A positive electrode plate, an insulating layer, a negative electrode plate, and a separator are provided, and the negative electrode plate includes a negative electrode current collector, a negative electrode active material layer, and a negative tab provided on the surface of the negative electrode current collector, the negative electrode active material layer covers the surface of the negative electrode current collector, and the negative electrode active material layer has a first groove for avoiding the negative tab, and the negative tab is located in the first groove, and for example, the negative tab may be welded to the first groove.

A first adhesive layer is provided on one side of the insulating layer, and the first adhesive layer may be a hot melt adhesive layer that is not sticky at room temperature. Specifically, the first adhesive layer may be applied to the surface of the insulating layer, may be attached to the surface of the insulating layer, or may be provided in another form on the surface of the insulating layer. A second adhesive layer is provided on the other side of the insulating layer, and the second adhesive layer may be a pressure-sensitive adhesive layer that can swell with an electrolyte, or may be another adhesive layer that can bond the insulating layer to the positive electrode plate. Specifically, the second adhesive layer may be applied to the surface of the insulating layer, may be attached to the surface of the insulating layer, or may be provided in another form on the surface of the insulating layer.

The surface of the insulating layer on which the second adhesive layer is provided is adhered to a predetermined position on the positive electrode plate, where the predetermined position is a position that will be aligned with the first groove on the positive electrode plate after the core winding is completed, i.e., the insulating layer attached to the predetermined position covers the first groove after the core winding is completed.

A separator and a negative electrode plate are sequentially stacked on the surface of the positive electrode plate to which the insulating layer is adhered, with the first groove on the negative electrode plate facing the separator. At this time, the surface of the insulating layer on which the first adhesive layer, which is a hot melt adhesive layer that is not sticky at room temperature, is provided comes into contact with the separator. Since the hot melt adhesive layer is not sticky at room temperature, the insulating layer does not adhere to the separator, which prevents adverse effects on the subsequent winding process.

A laminated structure consisting of a positive electrode plate, a separator, and a negative electrode plate is wound up to form a winding core, and at this time, the insulating layer attached to the positive electrode plate can cover the first groove, preventing lithium ions from passing through the insulating layer and entering the first groove.

The winding core is subjected to a heat press treatment, which increases the adhesion of the hot melt adhesive layer, which is not sticky at room temperature and comes into contact with the separator, thereby allowing the surface of the insulating layer on which the hot melt adhesive layer is provided to be adhered to the separator, and ensuring that the insulating layer covers the first groove relatively reliably.

In a concrete implementation, first bonding the insulating layer to the positive plate can provide good positioning for the insulating layer, ensuring that the insulating layer can accurately cover the first groove after the core winding is completed. The surface of the insulating layer that comes into contact with the separator is provided as a hot melt adhesive layer that is non-sticky at room temperature, which can prevent the insulating layer bonded to the positive plate from adhering to the conveying rollers of the equipment during the winding raw material supply process, causing the adhesive layer to fall off or the positive plate to tear, and can also prevent excessive dust from being adsorbed on the surface of the insulating layer, which can have a negative impact on the safety performance of the battery.

Furthermore, the second adhesive layer can be provided as a pressure-sensitive adhesive layer that can be swelled by the electrolyte. That is, after the winding core is enclosed in a shell and the electrolyte is injected, the electrolyte causes the pressure-sensitive adhesive layer that can be swelled by the electrolyte provided on the insulating layer to swell and detach from the positive electrode plate, thereby finally bonding the insulating layer to the separator, without impairing the performance of the positive electrode plate.

Figure 10 is a schematic structural diagram of a battery plate provided by an embodiment of the present application, Figure 11 is a side view of a battery plate provided by an embodiment of the present application, Figure 12 is a schematic structural diagram of a first side of a battery plate provided by an embodiment of the present application, and Figure 13 is a schematic structural diagram of a second side of a battery plate provided by an embodiment of the present application.

Refer to Figures 10 to 13. This embodiment provides a battery, which includes a plate 1 and a tab 2, the plate 1 includes a current collector, the current collector includes a first surface 3 and a second surface 4, the first surface 3 and the second surface 4 are both provided with a first active material layer, the first active material layer is provided with a first groove 5 and a second groove 6, the first groove 5 and the second groove 6 are provided opposite the first surface 3 and the second surface 4, the tab 2 is electrically connected in the first groove 5, and the area of the first groove 5 is larger than the area of the second groove 6.

The above battery plate is configured so that the area of the first groove 5 is larger than the area of the second groove 6, which makes it possible to avoid poor removal or damage to the plate due to the step between the first active material layer and the groove when removing the first surface 3, and to simplify the removal process.

Specifically, in this embodiment, in the direction of the connecting line between the first surface 3 and the second surface 4, the projection of the first groove 5 completely covers the projection of the second groove 6, and preferably, the area of the second groove 6 is 60 to 90% of the area of the first groove 5. For example, if the minimum distance between the adjacent sides of the first groove 5 and the second groove 6 is n, it is necessary to satisfy 0.5 mm ≦ n ≦ 3.5 mm. If the maximum distance between the adjacent sides of the first groove 5 and the second groove 6 is x, it is necessary to satisfy 0.5 mm ≦ x ≦ 3.5 mm. As should be explained, this is merely an example and not a limitation, and convertibly, in other feasible embodiments, the above-mentioned area ratio can also be adjusted to a certain extent.

As understood, a current collector refers to a structure or component that collects current, and in lithium-ion batteries, it is primarily a metal foil, such as copper foil or aluminum foil. The first active material layer is a coating that includes the first active material, and convertibly, the first active material layer is a multi-layer structure consisting of multiple coatings, where at least one coating includes the first active material.

In practice, it is necessary to physically remove the first active material layer on the plate body 1 using a scraper to expose the current collector with a good surface condition and connect the groove to the current collector substrate. The first active material layer referred to in this embodiment is a paste.

Optionally, the plate 1 includes a positive plate and/or a negative plate. In this embodiment, the positive plate is taken as an example. However, this embodiment is not limited thereto, and as a convertible embodiment, in another possible embodiment, the above-mentioned first groove 5 and second groove 6 may be provided in the negative plate. In another possible embodiment, the above-mentioned first groove 5 and second groove 6 may be provided in the positive plate and the negative plate at the same time.

It should be noted that, in this embodiment, the positive plate is provided with the first groove 5 and the second groove 6, but the number of grooves provided is not particularly limited in this embodiment, and is merely for illustrative purposes. As a convertible embodiment, in other feasible embodiments, two or other numbers of grooves may be provided in the same positive plate. The specific number is determined by the specific usage situation.

When installed, it is necessary that the projection of the first groove 5 completely covers the projection of the second groove 6 in the direction of the connection line between the first surface 3 and the second surface 4.

Optionally, the cross section of the first groove 5 and the second groove 6 is rectangular. In this embodiment, the cross section is a plane perpendicular to the connection line between the first surface 3 and the second surface 4.

Specifically, in this embodiment, the cross sections of the first groove 5 and the second groove 6 are set as rectangles. Here, when the cross sections of the first groove 5 and the second groove 6 are rectangular, the first groove 5 is regarded as the first surface of the rectangle, and the second groove 6 is regarded as the second surface of the rectangle, in which case the length of the first surface of the rectangle is greater than the length of the second surface, and the width of the first surface of the rectangle is greater than the width of the second surface. Conversionally, the cross section of the groove may be other regular polygons such as a parallelogram or a square. However, whatever the regular polygon, it is necessary that the tab 2 can be embedded.

As a convertible embodiment, in another possible example, the cross-section of the first groove 5 and the second groove 6 may also be an irregular polygon, where the cross-section is a plane perpendicular to the connection line between the first surface 3 and the second surface 4.

Specifically, in this embodiment, the cross sections of the first groove 5 and the second groove 6 are set so that the first surface 3 is trapezoidal and the second surface 4 is rectangular. Here, the area of the trapezoid should be greater than the area of the rectangle. Conversely, the cross sections of the first groove 5 and the second groove 6 may also be other irregular polygons, but any irregular polygon must satisfy that the minimum difference between the sides of the adjacent first groove 5 and second groove 6 between the trapezoid and the rectangle is greater than 0 mm and the tab 2 can be embedded.

As a convertible embodiment, in another possible embodiment, the cross-section of the first groove 5 and the second groove 6 is circular, and the cross-section is a plane perpendicular to the connection line between the first surface 3 and the second surface 4.

Specifically, in this embodiment, the cross sections of the first groove 5 and the second groove 6 are set to be circular. Here, when the cross sections of the first groove 5 and the second groove 6 are circular, the first groove 5 is regarded as a circular first surface, and the second groove 6 is regarded as a circular second surface, and in this case, the radius of the circular first surface is larger than the radius of the second surface.

Optionally, in this embodiment, the plane formed by the central axis of the first groove 5 and the central axis of the second groove 6 overlaps or is parallel to the connecting line between the first surface 3 and the second surface 4. This allows the tab 2 to be better embedded in the first groove 5. However, this embodiment is not limited thereto, and convertibly, in other possible embodiments, the central axis of the first groove 5 and the second groove 6 can be parallel to the connecting line between the first surface 3 and the second surface 4.

Based on Examples 1 to 3, this example provides an electronic device, which includes a battery.

The battery in this embodiment has the same structure as the battery provided in Examples 1 to 3 and achieves the same or similar technical effects, so it will not be repeated here and specific reference may be made to the description of the above embodiments.

In the description of this application, as should be further explained, the terms "installation," "mounting," "connection," and "connection" should be broadly understood unless otherwise clearly specified and limited, and may be, for example, a fixed connection, a removable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or an internal communication between two elements. Those skilled in the art can specifically understand the specific meaning of the above terms in the present application.

As an explanation, relational terms such as first and second are used herein only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that any such actual relationship or order exists between those entities or operations.

The above is merely a specific embodiment of the present application, and the scope of protection of the present application is not limited thereto. Any modifications or substitutions that are easily conceivable by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application is defined by the claims.

This application claims priority from a Chinese patent application filed on May 11, 2020 with the China Patent Office, bearing application number 202010393415.5 and titled "Winding core and manufacturing method thereof, battery and electronic product", a Chinese patent application filed on May 29, 2020 with the China Patent Office, bearing application number 202020953044.7 and titled "Battery structure and electronic device", and a Chinese patent application filed on June 19, 2020 with the China Patent Office, bearing application number 202021145599.5 and titled "Battery plate and battery", the entire contents of which are incorporated herein by reference.

Claims (13)

A battery comprising a first plate, a second plate and a separator, the first plate, the separator and the second plate being sequentially stacked and wound and installed;
the first plate includes a first current collector and a first tab, the first current collector includes a first surface and a second surface, the first surface and the second surface are both provided with a first active material layer, the first active material layer is provided with a first groove and a second groove, the first groove and the second groove are located on the first surface and the second surface, respectively, and are positioned opposite each other, the first tab is welded into the first groove, the first groove is covered with at least one insulating layer, and the second groove is covered with at least one insulating layer ;
The separator is selected from polyethylenes or polypropylenes, and the separator forms the insulating layer after the portion covering the first groove is heat-treated; and/or
the second electrode plate includes a second current collector and a second active material layer, the second active material layer covers a surface of the second current collector, and the second current collector has a non-active material layer region, the non-active material layer region facing the first groove . The battery of claim 1, characterized in that the first groove is covered with at least two insulating layers. The battery according to claim 2, characterized in that the second groove is covered with one insulating layer, and at least one insulating layer is provided in the area of the second plate facing the second groove. The battery of claim 3, characterized in that the length and/or width of the insulating layer in the area of the second plate facing the second groove is not greater than the corresponding length and/or width of the insulating layer in the second groove. The battery according to claim 2, characterized in that part or all of the insulating layers of the at least two insulating layers in the first groove cover the first groove. the second electrode plate includes a second current collector and a second tab, a second active material layer is provided on both opposing sides of the second current collector, the second active material layer is provided with a third groove and a fourth groove, the third groove and the fourth groove are located on both opposing sides of the second current collector, and are positioned opposite each other;
3. The battery of claim 2, wherein the second tab is welded into the third groove, the third groove and the fourth groove are both covered with an insulating layer, the first plate has an insulating layer in an area facing the third groove, and the first plate has an insulating layer in an area facing the fourth groove. The battery according to claim 6, characterized in that in the first plate, the length and/or width of the insulating layer in the area facing the third groove is not greater than the corresponding length and/or width of the insulating layer in the third groove, and in the first plate, the length and/or width of the insulating layer in the area facing the fourth groove is not greater than the corresponding length and/or width of the insulating layer in the fourth groove. The battery according to claim 1, characterized in that the first electrode plate is a negative electrode plate, the second electrode plate is a positive electrode plate, and the separator between the first groove and the second electrode plate is provided with an insulating layer that covers the first groove. The battery according to claim 8, characterized in that the insulating layer is adhered to the separator via a first adhesive layer, the first adhesive layer being a hot melt adhesive layer that is not sticky at room temperature, and/or a second adhesive layer is provided on the surface of the insulating layer opposite the separator, the second adhesive layer being a pressure-sensitive adhesive layer that can be swelled by an electrolyte. The battery of claim 1, characterized in that in the direction of the connecting line between the first surface and the second surface, the projection of the first groove completely covers the projection of the second groove, and/or a plane formed by the central axis of the first groove and the central axis of the second groove overlaps or is parallel to the connecting line between the first surface and the second surface. The battery of claim 1, characterized in that, when the cross sections of the first groove and the second groove are both rectangular, the length of the side of the first groove is greater than the length of the side of the second groove, the width of the side of the first groove is greater than the width of the side of the second groove, and/or the area of the second groove is 60 to 90% of the area of the first groove, and/or, where n is the minimum distance between adjacent sides of the first groove and the second groove, 0.5 mm≦n≦3.5 mm, and/or, where x is the maximum distance between adjacent sides of the first groove and the second groove, 0.5 mm≦x≦3.5 mm. The battery according to claim 1, characterized in that the second electrode plate includes a second current collector and a second tab, a second active material layer is provided on both opposing sides of the second current collector, a third groove and a fourth groove are provided in the second active material layer, the third groove and the fourth groove are located on both opposing sides of the second current collector, and are positioned opposite each other, the second tab is welded into the third groove, and the area of the third groove is larger than the area of the fourth groove. An electronic device, comprising the battery according to any one of claims 1 to 12 .

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